The namespace layer rejects malformed qualified names, declarations of
the xmlns prefix, misbindings of the xml prefix and either reserved
namespace name (including as the default namespace), and prefix
undeclaration; attributes must be distinct by expanded name; PI targets
and entity/notation names are NCNames; and DTD-typed xmlns values bind
their normalized form. Clears all 18 namespace cases from the eduni
baseline; xmltest valid/sa/012 joins the documented deviations per the
suite's own NAMESPACE='no' flag.
Closes#136
The eduni sections run with exact classified baselines. Fixes: 3.3.3
CDATA attribute-value normalization (literal whitespace to space before
reference decoding; char-ref whitespace survives; tokenized collapse on
SPACE only); production-68 lenient undeclared entities in content and
attribute values (validity finding, reference kept literal, nothing
fetched); errata E15 (references/comments/PIs/whitespace in EMPTY,
char-ref whitespace as data in element content, double-escape shape
included); errata E2 duplicate enumeration tokens; errata E14
declarations completed inside PE replacements (VC: Proper
Declaration/PE Nesting); NCName ID values; namespace declarations
subject to the every-attribute-declared rule. Reader validity machinery
split to EventReaderValidity for caps.
Closes#127
